Describing the mechanisms through which animal morphology evolves is a fundamental goal of biology. Adult morphology is produced through the processes and genetic networks that comprise development. However, most comparative developmental studies have focused on widely divergent species, obscuring morphologically significant molecular differences with those incurred over time through random genetic drift. To more directly investigate the evolution of developmental mechanisms underlying morphological diversification, the research proposed here will investigate the developmental network underlying antenna distal morphology in two closely related species of flour beetles, Tribolium castaneum and Tribolium confusum. This trait is evolutionary labile and tractable through modern techniques of developmental genetics. This work will help define the types of molecular changes involved in morphological evolution. Investigation into the development of these insects, which are agricultural pests and human parasite vectors, will also further the pursuits of pest management and human health.